Actress Katie Holmes on Tuesday filed a $50 million lawsuit, accusing celebrity magazine Star of libel for a cover story that falsely suggested she was a drug addict.

The lawsuit, filed in Los Angeles federal court, is over a January edition of the magazine with the cover line "Addiction Nightmare. Katie Drug Shocker!"

The inside story claimed that Holmes, the wife of Tom Cruise, was "trapped in a cycle of addictive treatments", but made no allegations of drug use. Instead it talked of counseling sessions in the Church of Scientology, according to the lawsuit.

Cruise is one of Hollywood's leading Scientology followers.

"Star Magazine's malicious claims about Katie are untrue, unethical and unlawful. Not only do they cruelly defame Katie, they play a cheap trick on the public, making ridiculously false claims on the cover unsupported by anything inside," attorney Bert Fields said in a statement.

Holmes, 32, is seeking $50 million in damages.

Star magazine, is published by Florida-based American Media Inc, whose group includes tabloid weekly The National Enquirer.

A spokeswoman for American Media said on Tuesday that the company would "vigorously defend" the lawsuit and that its attorneys "look forward to deposing Ms. Holmes about her experiences with Scientology."

Lawyers for Holmes said the actress was forced to file the lawsuit to "vindicate her reputation after American Media refused to retract its vicious lies about her."

Holmes's five-year marriage to Cruise has been a frequent source of speculation in the celebrity media.

The actress said in a statement on Tuesday that "of all the fabricated stories that continue to be published about me, this instance is beyond the pale. The publisher knew this outrageous story was false and printed it anyway to sell magazines."

Holmes made her name in the teen TV drama "Dawson's Creek" and went on to appear in movies such as "Batman Begins". She made her Broadway debut in 2008 in a production of Arthur Miller's play "All My Sons".